Electric motor follow-up system for the adjustment of liquid levels



Jan. 12, 1954 v. GENIM ETAL 2,666,172

ELECTRIC MOTOR FOLLOW-UP SYSTEM FOR THE ADJUSTMENT OF LIQUID LEVELSFiled Aug. 6, 1947 9 Sheets-Sheet l e p M f v, 1 1

I o, o

Jan. 12, 1954 5mm ETAL 2,666,172

V. G ELECTRIC MOTOR FOLLOW-UP SYSTEM FOR THE ADJUSTMENT OF LIQUID LEVELSFiled Aug. 6, 1947 9 Sheets-Sheet 2 Jan. 12, 1954 Filed Aug. 6, 1947 V.GENlNl ET AL ELECTRIC MOTOR FOLLOW-UP SYSTEM FOR THE ADJUSTMENT OFLIQUID LEVELS 9 Sheets-Sheet 3 Jan. 12, 1954 v N] ,ETAL 2,666,172

ELECTRIC MOTOR FOLLOW-UP SYSTEM FOR THE ADJUSTMENT 0F LIQUID LEVELSFiledAug. 6, 1947 9 Sheets-Sheet 4 Jan. 12, 1954 v ET AL 2,666,172

ELECTRIC MOTOR FOLLOW-UP SYSTEM FOR THE ADJUSTMENT OF LIQUID LEVELSFiled Aug. 6, 1947 9 SheetsSheet 5 5 v. GENlNl ETAL 2,666,172v

ELECTRIC MOTOR FOLLOW-UP SYSTEM FOR THE ADJUSTMENT OF LIQUID LEVELSFiled Aug. 6, 1947 9 Sheets-Sheet 6 Jan. 12, 1954 v GENlNl ET AL2,666,172

ELECTRIC MOTOR FOLLOW-UP SYSTEM FOR THE ADJUSTMENT OF LIQUID LEVELSFiled Aug. 6, 1947 9 SheetsSheet 7 Jan. 12, 1954 v. GENlNl ETAL2,666,172

ELECTRIC MOTOR FOLLOW-UP SYSTEM FOR THE ADJUSTMENT 0F LIQUID LEVELSFiled Aug. 6, 1947 9 Sheets-Sheet 8 Jan. 12, 1954 v GENlNl ET AL I2,666,172

ELECTRIC MOTOR FOLLOW-UP SYSTEM FOR THE I ADJUSTMENT OF LIQUID LEVELSFiled Aug. 6, 1947 9 Sheets-Sheet 9 Patented Jan. 12, 1954 STATES PATENToFFrcE:

ELECTRIC MOTOR FOLLOW-UP SYSTEM FOR THE ADJUSTMENT OF LIQUID LEVELSThe.v present. invention has in view a project fin. keeping, awater-lvel'i atav fixed mark by the automatic adjustmentlof the water.output. either through the. opening. or: raising of one. or moresluice-gates, or through regulating the. action. of one. or morehydraulic turbines.

sure,.. temperature, etc, by automatic action on one; or more of theadjustment, members o'fa variable. on which a particular dimension. ormagnitude depends; In order to. make things easier,howevenQthe."explanati'on of the invention will be; restricted to adiscussion on. the subject of water-levels.w

The. method; that. forms the object of the invention, includes mainly.by the setting, up. of a close connection between neighbouring. levelslocated? on each side of the theoretical level to be maintained and 1stages of opening of the. adjusting members,, a connection that may be"represented; as thecase may be; by a law involving measurementlinonedimensiononly or otherwise. For each figure; of levelincludedibetween the extreme ranges of? adjustment, there istonepositti'omandoneonIy, off the adjustingmember and by the level-detectorthrough the agency of; an

electric transmission, for the other, by thei'posie tion of theadjustment member: through: the agency at. any suitableri transmission;that maybe mechanical? or electrical.

m the i-generah setup thus outlined;. thereare 10 Claims. (01.- 318-31)numerous modifications, of the way in which, it may becarriecll intoeffect. 'I-hus, in the case, of a linear. lawlinkingv the changes inposition. of the. adjustment member with those. of. the level, thelevel-detector and. the electric transmission are among those able toconvey to thecomparing member that they control changes v of; positionthat vary linearly with alterations of. level, and there I are likewisemovements of. the second? comparing. member as a function of; themovements of'the adjustment member. In. thecase of nonlinear law, thedevice: mentioned above its-finished off by a suitable translationalmeans; inserted in one of the transmissions between the comparingdevice, on. the one hand, and the level-detector or adjustment member,on-thev other hand;

Electric transmissions employed are preferably transmissions of standardtype by rotating-field mechanisms.

A. worth-while improvement. to thefldevice men.- tioned above'lies theintervention otadifferential in one of the transmissions-connecting thecomparing members to the-level-detector and to the adjustment member,which allows a variation to be made in: the level ofthe-base-l-ine ofthe adjustment; this arrangement is preferably finished oii byequipmentall'owing the automatic adiustment, to be put ou-tof actionmomentarily, for instance by breaking the feed circuit of.- the motoractuating the. adjustment membenat the moment'when. thereis a change inthe level of theadjusting base-line caused by the difierential, andpreferably automatically preparing this ad justmentfor comingagain intoplay as soon: as the new level, as: decided, isreached.

For certain adaptations, and in accordance with another characteristicof the invention, the device comprises a; differential inserted in oneof the transmissions. connecting the comparing members to the-level-detector and to the adjustment member; this differential has oneof. its members controllable by a programmeter stopping V automaticallyfor predeterminedlevels. Preferably, another differential'is inserted inthe transmission connecting theprogrammeter tothe first differential andone of its members may be worked by hand. Thusformed, this device allowsachange-to be made in the theoretical adjustment level in accordancewith agiven law as afunction of time, and then: allows it tobe keptuniform-eta givenvalue: Such is the case, for instance, when; a:decision is made for the emptying and filling of a storagei-basin' orreservoir during fixedtimes;

Another important feature; of the method mentioned above, forming, as itdoes, another characteristic of the invention, lies in its combinationwith the adjustment method based on a fixed level, the latter methodonly being brought into action much more slowly than the first one andas a function of the loss of head occasioned by the action of this firstone in order to bring this loss of head step by step to zero throughaction on the main adjustment so as to alter the final statism.

The main adjustment thus allows a stable adjustment to be quicklyformed, but at the cost of a certain loss of head, and the balancingadjustment that acts slowly brings the level to its fixed value withoutgiving rise to any pumping.

To this end, the device forming the object of the invention comprises incombination with that previously described a balancing equipment made upof a difierential inserted in one of the transmissions connecting thecomparing members to the level-detector and to the adjustment member andactuated by an auxiliary electric motor having a control device for thefeed which comprises two contacts working together of which one isnormally stationary and the other connected, for instance, by electrictransmission to the level-detector.

As examples that are in no way restrictive various arrangements ofadjustment devices, in accordance with the invention, are showndiagrammatically in the accompanying drawings.

In these drawings:

Fig. 1 is a diagram illustrative of the adjustment method that forms theobject of the invention;

. Figs. 2 to 4 are assembly sketches of modifications of devices forputting the method into operation in accordance with the diagram of Fig.1;

Figs. 5 and 6 show in detail two modifications of the electric andmechanical equipment of devices according to Figs. 2, 3 and 4;

Fig. 7 is a similar sort of diagram to that of Fig. 1 and illustrates amodification of this method;

Fig. 8 shows, like Figs. 2 to 4, the assembly of a device for puttinginto operation the method in accordance with Fig. '7;

Figs. 9 and 10 illustrate in detail two modifica tions of the electricand mechanical equipment of the device in accordance with Fig. 8;

Figs. 11 to 14 illustrate other modifications for putting into operationthe method in accordance with the diagram of Fig. 1;

Figs. 15 to 17 show various modifications of devices provided with meansthat allow a varia- I tion to be made in the level of the adjustingbase-line.

Fig. 18 is a diagram illustrating the adaptation of the adjustmentmethod to the case of variation of the level of the adjusting base-linein accordance with a law given as a function of time;

Fig. 19 is a sketch of the assembly of a device for putting intoopera'tion'the method in accordance with the diagram of Fig. 18;

Fig. 20 shows in detail the electrical and mechanical equipment of thedevice of Fig. 19;

Figs. 20a and 201) are modifications of th equipment illustrated in Fig.20;

Fig. 21 is a diagram illustrating the method in accordance with thediagram of Fig. 1 in combination with a method for adjustment atconstant level;

Fig. 22 shows the assembly of a device of the method in accordance withFig. 21;

Fig. 23 shows in detail the electrical and mechanical equipment of thedevice of Fig. 21;.

Fig. 24 is a diagram illustrating amodification of the adjustmentmethod, a modification that comprises an adjustment fork conducing tothe maintenance of the equipment at the time of changesof direction ofthe variation of level; and

"Fig. 25 illustrates a device for putting the method into operation inaccordance with Fig. 24.

In Figs. 2 to 6 devices for adjustment of level have been illustratedarranged so as to adhere to the law of linear adjustment statism shownin Fig. 1 in which the levels are drawn as ordinates and the positionsof the adjustment member as abscissae. This law has been reasoneddeductively in allowing a maximum variation in level from N, to N2, inrecognising that the posi tion 0, of complete closure of the adjustmentmember corresponds to the lower level N, while the position 02 of fullopening corresponds to the upper level N2, and finally that themovements of the adjustment member as a function or the level areproportional to the variations of this level. Thus is obtained thestraight line N, P of linear adjustment. To every intermediate point Pof this straight line N, P there is a corresponding level N and aposition 0' of the adjustment member that fulfill the conditionmentioned above. v

The adjustment device arranged to fulfill'this law comprises here alevel-detector I and an electric transmission 2 of the signals of thisdetector I to a control device 3 of a two-way motor connected, so as tobe able to actuateit, to the adjusting member 5 of the consumption, thatis itself I connected on the other hand through a transmission 6 to thecontrol device 3. In Fig. 2, the adjustment member is a quadranttypegate, in Fig. 3, it is a sluice-gate and, in Fig. 4, it is the gate of aturbine I. In all these cases, the level-detector is standard equipmentof the floater type 8 (Fig. 5) of which the displacements in height areconverted to an angular displacement of a member 9. The latterdrivestheshaft of a transmitter I 0, forming partof an electrical transmissionthrough rotating field gear working either on direct current oralternating current (feed method only shown here) besides thetransmitter I0, this transmission comprises a receiver I I formed byanother rotating-field mechanism. On the other hand, the motor 4, thatworks the adjustment member through the agency of the mechanicaltransmission I2, is fed by a control device comprising twocontact-makers I3, I4, in parallel in the electrical network, butreverse'connectedon the motor and of which the windings are connected inparallel in the feed circuit with the intervention of a distributor madeup of a rotating arm I5 that carries a contact roller running on a ringshowing two semi-circular areas I6 separated from each other by twoinsulating areas I! and ll of which one, I1, is narrow and use is madeof it in the working system. The areas I6 are connected respectively tothe windings of the contact-makers I3, I4. The control arm I5 and thecontrol ring are connected respectively to receiver II and totransmission I2 through transmissions I8, IS in reference to constanttransmission.

The system works as follows:

On stopping, the contact roller of arm I5 is on the insulating area I1.If a variation of level occurs, the member 9 has an angular movement .justment member. v.tors 2| and 22 comprises a moving sector 23 andthrough an amount proportional to this variation Sand, through theagency of transmitter 10 and receiver imparts to arm I5 an angularmovement in proportion to its own. One of the elecbro-contact makers|3-|-'| is thus excited, with its circuit closed by the contact rollercoming on one of the conductin areas I6, and closes, thus .Jeeding themotor 4 that then Works the adjustment member; but at the same time thetransmission 19 causes the control ring to rotate and I the latterfollows the movement of arm l5 up till the moment, when the latter beingstopped, the rotation of the ring brings the insulating area all incontact "with the roller, which cuts the feeding of motor 4: the latterstops and at this very instant the adjustment member is in the positionfixed by the law of Fig. 1,

In the example outlined above, the electric --transmission l 0, H is ofthe continuous displace- ...mentitype so that every variation of levelinvolves =2. movement of the ad-justmentmember.

In the layout illustrated in Fig. '6, on the other hand, the controldevice is formed by an intermittent transmission of standard patternthat allows the adjustment member to occupy a re- 1 stricted number ofpositions corresponding to the same number of level equivalents.

device comprises a transmitting distributor 25 having a plug 2'16 whichis moved by the leveldetector.

This distributorfeeds in parallel the fixed studs 18 and I9 of twodistributors 2| and 22 of which the movements are interdependent andthat are controlled by the shaft |;9 actuated by the .ad- Therotatingpart of distribu- 14 allowing the feeding of studs 18 and 19.

The distributor 2| induces the running of motor ,4 in one direction anddistributor 22 causes the motor to run inthe other direction.

When the roller 25 comes in contact with one of the fixed studs of thedistributor :2 5, it feeds the fixed studs 18 and 79 so that, accordingtothe respective positions of the roller 32 5 and rotary distributors 2|and 2?, the studs '78 and 19 come in contact with the conducting sectors23 and 24, which causes the starting of motor 4 through the agency ofrelays I3 and 14.

When the motor 4 has travelled through the ang-lecorresponding to themovement of the roller .26, the circuit closed by this roller is againopened,

with the conducting sectors 23 and 24 occupying at thisinstant .aposition similar to that of Fig. 6. The relays l3 and M drop causing thestoppage of motor 4.

.It must be observed that the number of positions, in the case of theexample selected, is re- ,.-.stricted to the number of fixed studs onthe .dis-

arrangement allows, by calling 'p'the number of studs of eachintroductiontransmission and nthe number of the latter, to ensure anumber of posi- -tions .Pn, the number of conductors being only Insteadof a lav: of linear adjustment such as and the adjustment member. oflinkup between the control device and the adillustrated in 'Fig. 1,there may be preference for a law adjustment illustrated by a cure C(Fig.7) going through the clearly defined end points N1 and P asexplained above with reference to Fig. 1. To effect this law, atranslational means 28 (Fig. 8) is placed between the adjustment member5 and the control device 3.

This translational means may be, for instance, of a standard type formedby a balance-beam and cams with suitably designed contour to effeet alaw of variation as illustrated by the curve C of Fig. 7.

This type of translational means shown very diagrammatically in Fig. 9comp-rises a balancebeam 1'3 that can swin around an axis 80. The lowerpart of the beam comprises a roller 14 running between two control cams29 of suitable shape to effect the translational law to be adhered to.

The balance-beam transmits the translated angles to the shaft I9 drivingthe control device, by means of a toothed sector 15 located at its upperpart actuating pinions 16 and 11.

In accordance with the standard arrangement this type of translationalmeans allows the fulfilment of various laws of variation, on the onehand through suitable shaping of cams 29, and on the other hand bydisplacement of the axis of rotation 88 in relation to balance-beam 13.

The device illustrated in Fig. 10 varies from that shown in Fig. 9 bythe fact that the translational means 2 2 is inserted in the mechanicaltransmission l8 *connecting'to the control device l5, i the receiver Hof the electrical transmission coming from the level-detector Anotherdiiierence lies in the fact that the control device l5, it instead ofbeing connected through a mechanical transmission to the adjustmentmember is connected through the agency of an electrical transmissionwith a rotating field mechanism, comprising a receiver 3t! driving thearm I 5 of the control device and a transmitter 3| connected to themechanical transmission 1 2 between motor '4 This modification justmentmember may also be employed in the case of devices illustrated in Figs.5, 6 and 9, as shown in Figs. 11 to 14 by several examples. In Fig. 11,in other respects similar to Fig. 2, may be seen at 32 the electrictransmission placed between the adjustment member 5, in the shape of aquadrant gate, and the control device 3. Fig. 12 shows in greater detailthis transmission in the case of an installation similar in otherrespects to that illustrated in Fig. 5: the transmission by a rotatingfield mechanism comprises a transmitter 3| mechanically connected to theadjustment member '5 and a receiver 36 driving mechanically the controlrings I6. The arrangement illustratedin Fig, 13 is only a modificationof the previous one since the electrical transmission-s, formed by thetransmitter Hi and receiver H and transmitter 38 and receiver 3| comingrespectively from the level-detector i and the adjustment member,

no longer actuate directl the control device I5,

the level causes the primary 35 to rotate and initiates a displacementof the planet-gear carrier 36 and oi the-arm 'l 5'thus starting up themotor the resulting displacement of "the adjustment member causes thesecondary '35 to rotate in are...

f the hand-wheel 42.

= verse direction andthus brings back the planetgear carrier 36 and armI5 to the starting position. Instead of the two receivers II and 30 andthemechanical differential 34, 35, 36, application may be made of thedifferential receiver 31 connected to the two transmitters I and 3| andof the roller-carrying arm I5, as shown in-Fig.

14 that is in other respects identical with Fig. 13.

In the arrangement illustrated in Fig. 15 a differential 39, 40, 4| isinterposed in the transmission between the adjustment member and thecontrol device I6; the planet-gear carrier of this differential may bemoved by hand by turning This action allows an alteration in the settingof the control rings I6 in relation to the adjustment member 5, whichhas .the effect of actuating the device so as to bring .the adjustmentmember 5 into a new position fixed by this offset, thus setting up a newrela- -tionship between the levels and the positions of .the adjustmentmember. I

In other respects, the control device undergoes contact maker 44 that,on the one hand, controls the feeding of contact-makers I3 and I4 and,on the other hand, is connected in the network by a main 4! including apush-button switch 48. This switch is closed normally and the workingprocedure is as follows: Through the opening of the push-button 48automatic working is held up; the

electric contact-maker 4,4 is no longer excited, cuts the excitercircuit 43 of contact-makers |3 and I4 that are thus locked and cutpermanently the feeding of the motor 4; the automatic working of thedevice is consequently held up.

In order to alter the reference level of the adjustment the controlrings I6 are offset by means of the hand-wheel 42; the roller of arm I5is in contact with one of the rings I6 but the contactmakers I3 and I4cannot be excited, the coil circuit being cut through a contact of therelay 44 and the setup consequently remains in the inoperative position.When the position of the adjustment member (located in any way, forinstance, by hand) corresponds to the reference level, the roller of armI5 is on the stud 46; through the main 45 the circuit of thecontactmaker 44 is closed. The electric contactmakers I3 and I4 arereleased and allow the automatic working of the setup that acts as inprevious setups; on the other hand the relay 44 is .kept self excited byconductor 41 up to the opening of the switch 48 and this is the case inspite of the separation of the contact roller of arm I5 and the stud 4G.

The device illustrated in Fig. 16 varies from the previous one by thefact that, on the one hand,

.the differential 39, 43, 4| for the control of adjustment of level isinserted between the receiver II of the electric transmission comingfrom the level-detector I and the control arm instead of being placedbetween the adjustment member 5 and the control device and that, inother respects, the arrangement comprises an electric transmissionbetween the adjustment member 5 and the control device as illustrated inFig. 12.

In the same Way the layout illustrated in Fig. 17 shows the applicationof this same control device for adjustment of level to the adjustmentdevice as shown in Fig. 14. I Y Fig. 18 illustrates the adjustment of alevel varying between two ranges N and N during a .given time intervalTH and in such a way that at moment T the theoretical level is N.

all)

This is the case shown when it is desired to vary the theoretical levelaccording to a law given as a function of time, then to hold it constantat a given value, for instance, when it is a question of emptying andfilling a reservoir during fixed periods.

With the adjustment carried out for a given condition, the level at timeT will ,be included between values P and P level limits that are locatedon the envelope curves C and C and that correspond respectively withfull opening and full closure of the adjustment member.

The assembly of the device illustrated in Fig. 19 comprises then aprogrammeter 5| in addition to the component units of the adjustmentdevice with possible variations in the base-line level of theadjustment. In the setup of such an arrangement as illustrated in Fig.20, the adjustment device is of the pattern shown in Fig. 12 and, asexplained in reference to Fig. 15, there is, be-

- tween the receiver 30 of the position of the adjustment member and thecontrol rings I6, a diiferential 39, 40, 4| that allows a variation tobe made in the base-line level of the adjustment. In this case, it isthe planet-gear carrier 39 of this differential that is driven throughthe receiver 30 and the sun-and-planet gear 4| that is connected to thecontrol rings I6. The other sun-and-planet gear 43 is driven by acontrol shaft 53 that is itself connected to the programmeter made up ofa speed-changer 51 that drives this shaft and that is actuated by anelectric motor 58 fed through a current reverser 59 and a contact-makerwith closure controlled by push-button 6| and with opening controlled bycontacts 62, 63 working with a movable cleat 64 driven by shaft 53.A'differential 54, 55, 56 is arranged between the control shaft 53 andthe programmeter. The planet-gear carrier 55 of this differential 54 to56 is workable by a hand-wheel 65.

By pressing on the push-button 6|, the motor 58 is started up in adirection fixed by the reverser 59 and the shaft 53 is driven at a speedregulated by the speed-changer 51. The differential 33 and 4| thencauses a progressive variation in the setting of the control rings I 6in relation to the receiver 3|] of the position of the adjustmentmember, which causes a variation in the base-line level of theadjustment as explained above in reference to Fig. 15. When the settingof the ring I6 corresponds to the desired base-line level, the movablecleat 64 that moves progressively along the shaft 53 meets and opens oneof the contacts 62, 63, thus stopping the working of the programmeter.The device consequently acts so as to hold fixed the new base-linelevel.

The working of the hand-Wheel 65 allows the location of the fixedreference level for adjustment to the initial time point. In otherwords, by referring to Fig. 18, it allows the positionin of level N attime T.

It allows, moreover, if running without 7 a programmeter iscontemplated, the actuation of the control shaft 53 so that any valuefor the adjustment may be selected. 7

The programmeter, of course, may be combined with any one of the devicespreviously described. In the same way, the device may include atranslational means between receiver II and arm I5 if the law ofrelationship between the level and the positions of the adjustmentmember is otherwise than linear; a translational means may also beinserted between the speed-changer 51 .and

shaft 53 if the law of variation of level has not the adjustment mernb vJust as in the device of Fig xl5'j -ajutdrnatie dm eraztionmaybeheldjup" as long" 22s the predetermihed zone' is not: ehteredr. To"this end;- a: switch 84' is placeck between rings 82 and: eon;-tabt=makers I 3 and' l 4" lackingany actionhf" the device on themotdr 4.7

With "transmission? revolving acertai'n'numoer ofitimes-"for".thetotalamplitude of the variation of? level, a? device may be ;inser.ted irrthe driving- Shait'S of transmitter lll wit-h' theieffeetwf en suringthe'automatic resetting of the transmis I sion'when', owing to a;current breakdown for in- 55 stance; the level may havechange'd in valuewith-. out-any indication of thischange" on'the partof the:transmission:

This" device" may be formed by an" automaticdiseng'aging systemcontroiiedhy a; lewvoltage'relay: The transmitter H3; on this"a'c'count,re'-" mins sta'tioriary inthe case -0f' wcurrent break sembly81 NT' When in" previous methods" this let'el 19 bnip iris'hh' devicewill have its toner 6n the sWitch-pfi. e y

In order 176' the" dreiwha ek's or 197cm? volttt'ge for the" case wherethe trtmsmissibn 2 cat-ties out sevra'gl tu'rljis'iaj bibeking (ifcurrent meyiqe arrefigetr also an the wincii'ng 'druni ensuring that theWlfidiiidll'lffl is stationary as SOon as there islekofvolt'eig'i e 4This arrangement requires the piovisipn of a spciiistyle of fl'qei 'thVVhile' the latter fehIEih'S stetmnsry as a, consequence of the trackinthe drum; it] is necessary in" fact that the evel alter and speciallyrise; tyithgut any tendeii'eyoflt fl elrtof' the Heat to fpllew thestove: merit for: this pt pqse, the'jfioat is: baua'ste'd in" 511011 atWay that the filkfimda'fi pressure is less t an the Weight or the float;on 'aibotifit Of the bl'o'kihg" Of the drum, with the 'bilhtfweightnothevingan effect, the fibat m'atti thus be submerged. In thecase f a falling level: the flO-ztt" stays hanging" tg')- it's'rope;When the fe'eq ing' curr nt is on again, the c urrehtji'slunblb'bke'd inthe dru'ni' and the float resumes it's previbus balanced iosit'ion; Totrevent the dev' formed by the" qrum'gnbat' ana= counterweight assembmfrom decelerating tO'O ra'gi idly, e'sgfiifill'j if it is aquestion of large changes" in le'vy a; dash-pot or equivalent form ofechanism ma be arranged and eontr sned by shaft 9 a 1 re' st'rib'tin'gat'qne enqthesame time the speed" iiid" degreeof ac'ce'leratibhoftheassembly Fig. 201) is a modification of preiiiOii'sTeir range'mentin Whiehthelposit'idn of the adjiistme'nt' rriemb'e'r is'no ldiigrconveyed by an elec? trical linkup but transferred directly b s'halft l9asin Fig.'15;

Figs. 20a. and 2 01) may be carriedoiitiri rfibj dified form by means(if electric" tra'fi'sinis' of standard mu ti-eircuitftyp, with the'siow cirj GuitWpr'eIimineJry' o eratitsm' centrbuizig" the" s 1 1 vice ofone of the types described previously, of the pattern of that in Fig.11.

In the example of execution described in Fig. 23, this furtheradjustment device comprises an auxiliary electric motor unit of whichthe motor 68 drives, through the agency of a suitable reducing gear, theplanet-gear carrier of a differential 69, for variation of the base-linelevel of adjustment, placed between the receiver ll of the level and theroller of arm IS. The control device of this motor 68 comprises twocontactmakers Ill-1| for reversing current in the motor, connectedrespectively to two conducting areas ii of a stationary control ringworking with a contact roller carried by a rotating arm l5 connected toan electric receiver of position 12, feed by the level-transmitter l0.Possibly, the receiver 12 might merge with receiver 1 I that wouldactuate the control arm I 5. It is evident that any variation of levelthat brings into plate the main device for adjustment is alsotransmitted to the control arm I5 which provides the starting-up of themotor 68 and, consequently, through the agency of a suitable reductionmechanism and of the difierential 69, a slow offsetting that may beelectric or mechanical, for causin a variation in the speed of the motor68 as a function of the extent of the initial off-setting recorded bythe outfit.

. The ring l6 may also be arranged at the transmitting station and alsothe control arm l5 of the further adjustment device and the arm l5 maythen be driven directly by shaft 9 of the floater drum 8.

l The device may comprise also any suitable translational means forsetting up a special law of relationship between the variations of leveland the positions of the adjustment member.

It may be noted that the area I! allows regulation of the extent of theinsensitiveness of the system around a given level.

- This adjustment may be of interest in the majority of cases in orderto avoid a continuous functioning of the layout. By acting on the widthof area I1, it thus becomes possible to restrict the number of timesthat the adjustment member starts up during a given period, whilepreserving for the layout at one and the same time its extremeadjustment ranges.

The diagram of Fig. 1 corresponded to the ideal case of an area ofextremely narrow width. When the width of the area increases, theworking diagram is shown as indicated in Fig. 24, while Fig. 25illustrates the respective positions of the roller and the switch-oil H.

In Fig. 24, the variations in level are provided between end limits Nand N the insensitiveness of the system expressed as a height of thelevel being equal to the distance N N' This insensitiveness ofadjustment is determined by the extent of the insulating area I! (Fig.25) separating the rings [6 of the control device. The importance ofthis area is such that the angular travel of the roller of arm l5corresponds to the distance between the levels N N' If the parallelogramis regarded as bounded by the two parallels N P and WP on the otherhand,

and the ordinates O and O on the other hand, the continuous incrementsof level will be eflected on the straight line N, P in the direction ofarrow F, while continuous falls in level will be effected on the curve PN in the direction of arrow F. Apart from the continuous falls andcontinuous rises, every movement of level is conveyed by a displacementof the roller of arm IS on the area I! that has no influence on theadjustment mem ber.

Under these conditions the position of this member remains unalteredduring all the travel of the roller of arm [5 along the area II. Inpractice, if we assume that the level increases and goes in a continuousway from N to N" the adjustment member takes a position 0' while theroller is in the position of Fig. 25 (full line). At this moment, if thelevel falls the roller moves according to arrow F and comes in contactwith the area l1. As pointed out above the adjustment gear is notactuated and the result of this is that the level may fall from Q to Rwithout any reaction from the gear; the adjustment member is held in theposition 0.

If at this moment the level rises, the roller travels over the area I!in the direction of arrow F, without any resulting movement of theadjustment member. Consequently for all the positions of the adjustmentmember, whatever they may be, (for instance for the position 0) it ispossible to vary the level from R to Q and from Q to R without bringinginto action the adjustment gear.

Naturally, in the previous assumption, when the level, after havingfallen from Q to R keeps on falling, it then moves on the straight lineRN, in the direction of arrow F.

This method of adjustment may be added, of course, to any one of thedevices illustrated in the previous figures.

As will be naturally understood the invention is in no way restricted tothedisclosed forms of execution that have been submitted only asexamples.

What we claim is:

1. In an electric control system, a movable member of varying position,a follow-up device comprising a followed movable member and a follower,an electric transmission form said movable member to said followedmember and whereby the latter is given a position depending upon that ofsaid movable member, a regulating member, an electric motor adapted toactuate the latter, an electric circuit adapted to feed said motor andcontrolled by said follow-up device so as to be open for at least onepredetermined relative position of the followed member and of thefollower, motion transmitting means from said motor to said follower,and adjusting means arranged to interfere with at least one of theoperative connections of said follow-up device with said movable memberand regulating member, respectively, whereby to vary the position ofsaid regulating member for atleast one end position of said movablemember and consequently the control action of the system.

2. In an electric control system, as in claim 1, said adjusting meanscomprising a differential gear.

3. In an electric control system as in claim 1, switch means included insaid motor feeding circuit and operable at will momentarily to put thevelectric control system out of operation.

4. In an electric control system as in claim 3, means providing for selfre-starting of the control system upon said movable member coming to apredetermined position, whereby to constrain the control system to beoperative for a range of positions of said movable member on one side ofsaid predetermined position despite said switch.

5. In an electric control system as in claim 2, a programmeter drivinglyconnected to one member of said differential gear and adapted toautomatically stop for predetermined positions of said movable member.

6. In an electric control system as in claim 5, a second differentialgear forming part of the driving connection between the programmeter andthe first difierential and means whereby one of the gear wheels of saidsecond differential may be actuated at will.

7. In an electric control system as in claim 2 means adapted to beresponsive to the cause of the actual positions of the movable memberand capable of operating one of the gear wheels of said differential.

8. In an electric control systemv as in claim 1, means responsive tooperation of said adjusting means and adapted to hold said follow-updevice in inoperative condition upon actuation of said VICTOR GENINI.MARCEL LATAPIE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 935,327 Routin Sept. 28, 1909 1,388,632 Dean Aug. 23, 19211,582,715 Wensley Apr. 27, 1926 1,832,809 Hudson Nov. 17, 1931 1,954,142Moffett Apr. 12, 1934 2,090,812 Schmitt Aug. 24, 1937 2,119,061 SteinMay 31, 1938 2,139,482 Atz Dec. 6, 1938 2,420,523 Davis et a1 May 13,1947

